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Re: Genuine Quantum Randomness

by dws (Chancellor)
on Jun 01, 2001 at 23:03 UTC ( [id://85030]=note: print w/replies, xml ) Need Help??


in reply to Genuine Quantum Randomness

For another random number generator based on a chaotic system (lava lamps), see http://lavarand.sgi.com/.

This wins points in my book for one of the coolest applications of lava lamp technology.

Update: They're defunct. Poo.

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Re: Re: Genuine Quantum Randomness
by John M. Dlugosz (Monsignor) on Jun 01, 2001 at 23:08 UTC
    I looked at lavaland just the other day, and it seems to be defunct. No updates in a couple years, and plans for stuff that may get done during 2000. Can't get any freshly generated random data from them.

    If I were to build something, I think a radio tuned to no station, patched to the mic input on a sound card would be a good and cheap chaos sampler.

    How does the random number generator in Perl's rand work? It seems pretty good, and I remember years ago reading that they no longer use the C library's generator.

    —John

      From the perldelta for v5.6.0:

      Better pseudo-random number generator
      In 5.005_0x and earlier, perl's rand() function used the C library rand(3) function. As of 5.005_52, Configure tests for drand48(), random(), and rand() (in that order) and picks the first one it finds.

      These changes should result in better random numbers from rand().

      ~monk d4vis
      #!/usr/bin/fnord

        Hmm, it looks like that doesn't apply to the ActiveState build. Looking through the source, it just calls rand(), which happens to be

        holdrand = holdrand * 214013L + 2531011L) >> 16) & 0x7fff)

        which I thought was brain-dead but seems to pass tests for randomness including chi-square. Owell.

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